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101.
A number of new synthetic methods for π‐conjugated oligoene and enyne compounds are described. Thus, diene and higher oligoene derivatives are selectively constructed by palladium‐catalyzed arylation reactions of internal alkynes in the presence of arylboronic acids or alkenes as terminators. In contrast, the synthesis of various enyne derivatives is achieved effectively by homo‐ or cross dimerization of alkynes under rhodium catalysis. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 326–336; 2008: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20158 相似文献
102.
Hayato Asanuma Dr. Kazuya Kanemoto Tokiharu Watanabe Prof. Dr. Shin-ichi Fukuzawa 《Angewandte Chemie (International ed. in English)》2023,62(18):e202219156
Synthetic methods for unsymmetrical disulfides are greatly needed owing to their applications in drug discovery, linker chemistry, and materials sciences. In this study, a new shelf-stable and easy-to-prepare bilateral disulfurating platform molecule, N-(morpholine-4-dithio)phthalimide, has been developed for the divergent synthesis of unsymmetrical disulfides. The amino and imide leaving groups of this reagent can be orthogonally transformed. Under acidic conditions, the amino moiety undergoes selective protonation and thus can be displaced by various carbon nucleophiles, such as allyl trimethylsilanes, alkynyl silanes, and electron-rich arenes, leaving the phthalimide moiety untouched. Meanwhile, the phthalimide leaving group is amenable to substitution under basic or neutral conditions. The combination of these transformations provides rapid access to diverse unsymmetrical disulfides through two C−S bond-forming reactions. 相似文献
103.
Dr. Kazuhisa Yamasumi Kentaro Ueda Dr. Yohei Haketa Dr. Yusuke Hattori Prof. Masayuki Suda Prof. Shu Seki Dr. Hayato Sakai Prof. Taku Hasobe Ryoya Ikemura Prof. Yoshitane Imai Dr. Yukihide Ishibashi Prof. Tsuyoshi Asahi Dr. Kazuto Nakamura Prof. Hiromitsu Maeda 《Angewandte Chemie (International ed. in English)》2023,62(8):e202216013
Squarylium-based π-electronic cation with an augmented dipole was synthesized by methylation of zwitterionic squarylium. The cation formed various ion pairs in combination with anions, and the ion pairs exhibited distinct photophysical properties in the dispersed state, ascribed to the formation of J- and H-aggregates. The ion pairs provided solid-state assemblies based on cation stacking. It is noteworthy that complete segregation of cations and anions was observed in a pseudo-polymorph of the ion pair with pentacyanocyclopentadienide as a π-electronic anion. In the crystalline state, the ion pairs exhibited photophysical properties and electric conductivity derived from cation stacking. In particular, the charge-segregated ion-pairing assembly induces an electric conductive pathway along the stacking axis. The charge-segregated mode and fascinating properties were derived from the reduced electrostatic repulsion between adjacent π-electronic cations via dipole–dipole interactions. 相似文献
104.
1,4-Addition of arylboronic acids to acrylic acid derivatives proceeds efficiently in the presence of a palladium catalyst system of Pd(OAc)2/(PhO)3P to produce the corresponding 3-arylpropionic acid derivatives. The use of the phosphite ligand is the key to conducting the addition smoothly with suppressing the competing Mizoroki-Heck-type oxidative coupling. 相似文献
105.
Tatsuya Nabeshima Hayato Miyazaki Atsushi Iwasaki Shigehisa Akine Toshiyuki Saiki Chusaku Ikeda 《Tetrahedron》2007,63(16):3328-3333
On the basis of the concept of partial template, triangular trisaloph ligands 2a and 2b reacted with excess ZnII to give heptanuclear Zn clusters with a similar geometry. The Zn complex of 2c, which was difficult to be prepared according to a previous procedure, was synthesized in high yield in a one-pot fashion. Various multi-nuclear complexes of 2a with Mn, Co, Ni, and Cu were also produced, although the trinuclear MnII and CoII complexes were smoothly oxidized to the MnIII and CoIII complexes. 相似文献
106.
Yamanaka H Moriyoshi K Ohmoto T Ohe T Sakai K 《Applied biochemistry and biotechnology》2007,136(1):39-51
Novel bisphenol A (BPA)-degrading bacterial strains, designated as BP-2CK, BP-21DK, and BP-22DK, were isolated from kimchi,
a traditionally fermented food. These isolates were identified as Bacillus pumilus and efficiently degraded BPA in a medium supplemented with nutrients such as peptone, beef extract, and yeast extract. Strains
BP-2CK, BP-21DK, and BP-22DK successfully degraded 25, 25, and 50 ppm of BPA, respectively, and all strains exhibited BPA-degrading
activity in the presence of 10% NaCl. Accumulation of the metabolites including 4-hydroxyacetophenone, one of the intermediates
produced by the other BPA-degrading bacteria, was not observed in BPA degradation by the isolated strains. These results indicate
that the isolated food-derived bacteria are applicable for the construction of efficient and safer systems for the removal
of BPA. 相似文献
107.
Namai H Ikeda H Hoshi Y Kato N Morishita Y Mizuno K 《Journal of the American Chemical Society》2007,129(29):9032-9036
The results of an investigation of the thermoluminescence (TL) and electroluminescence (EL) of arylated methylenecyclopropanes 1, systems whose photoinduced electron-transfer (PET) chemistry has been thoroughly studied, are described. In both the TL and EL experiments with 1, electronically excited triplet trimethylenemethane (TMM) biradicals (3)2** are generated by back electron transfer (charge recombination) of a TMM radical cation (hole) 2*+, formed by isomerization of the substrate radical cation (hole, 1*+). The application of this chemistry to the design of new organic light-emitting diodes (OLEDs) is described. The mechanistic features of this reaction system have the potential of overcoming significant problems (e.g., quantum efficiency, difficulty obtaining long wavelength emission, and device durability) normally associated with OLEDs that rely on the use of organic closed-shell hydrocarbons. 相似文献
108.
Hayato Toda Shuhei Otake Akari Ito Prof. Dr. Makoto Miyasaka Prof. Dr. Michiya Fujiki Prof. Dr. Yoshitane Imai 《Chemphyschem》2021,22(20):2058-2062
This paper reports the first magnetic circularly polarized luminescence (MCPL) characteristics of racemic helicenes, including four unsubstituted [n]helicenes (n=3,4,5,7) and two [4]helicene derivatives bearing methoxy substituents, in tetrahydrofuran (THF) and dimethyl sulfoxide (DMSO) solutions. The value of |gMCPL| was calculated to be of the order of 10−3 T−1 within 350–430 nm under the north-up (N-up) and south-up (S-up) Faraday geometries in an external magnetic field of 1.6 T. The [n]-dependent MCPL signs were altered by the N-up and S-up geometries. 相似文献
109.
Aryl migration reactions of C-3 aryl substituted pyrrolidinoindoline compounds to provide highly conjugated C-2 aryl indole compounds have been discovered. The developed reactions have a wide substrate scope and proceed in high yield under simple acidic conditions. A unique cationic cyclopropane intermediate as the transition state is proposed. 相似文献
110.
Kobayashi M Morimoto M Sato H Sato H 《The Journal of the Acoustical Society of America》2007,121(1):251-256
For ideal speech communication in public spaces, it is important to determine the optimum speech level for various background noise levels. However, speech intelligibility scores, which is conventionally used as the subjective listening test to measure the quality of speech communication, is near perfect in most everyday situations. For this reason, it is proposed to determine optimum speech levels for speech communication in public spaces by using listening difficulty ratings. Two kinds of listening test were carried out in this work. The results of the tests and our previous work [M. Morimoto, H. Sato, and M. Kobayashi, J. Acoust. Soc. Am. 116, 1607-1613 (2004)] are jointly discussed for suggesting the relation between the optimum speech level and background noise level. The results demonstrate that: (1) optimum speech level is constant when background noise level is lower than 40 dBA, (2) optimum speech level appears to be the level, which maintains around 15 dBA of SN ratio when the background noise level is more than 40 dBA, and (3) listening difficulty increases as speech level increases under the condition where SN ratio is good enough to keep intelligibility near perfect. 相似文献